Blasting powder



Patented Nov. 8, 1938 UNETED STATES PATNT OFFCE BLASTIN G POWDER Land 8.Byers,

Glendale, Calif.

3 Claims.

This invention relates to blasting powder and has for its object animprovement in explosive compositions suitable for general blastingpurposes which will have important advantages over i black powder.

Among the advantages of my improved powder over blasting powder may bementioned a lesser density with same heave or moving power, greater rateof decomposition upon explosion, more resistant to water or moisture,much less subject to ignition from shock or friction, not subject toignition from contact with ordinary flame, no poisonous fumes, and withall cheaper and quicker to manufacture.

Briefly described my improved blasting powder may be said to comprise aloose mass of sodium nitrate kernels, each of which is entirelyenveloped by an adherent layer of explosive agents adapted to form asubstantially balanced fortified and sensitized entity complete itself,and exhibiting all of the characteristics above enumerated.

My improved blasting powder consists of the following ingredients:

Percent by weight 5 Pelleted sodium nitrate 90 to 80 A liquid nitro body(liquifiable at modcrate temperatures) 3 to 6 Ammonium nitrate 3 to 6Potassium perchlorate 3 to 6 Powdered aluminum l to 2 (1) Minus 6 mesh,plus 8 mesh (2) Minus 8 mesh, plus 10 mesh (3) Minus 10 mesh, plus 12mesh,

and so on up to minus 36 mesh, plus 40 mesh.

The finer mesh pellets are employed where increased rate of combustionor greater brisance in the blasting powder is desired, and vice versa.

This pelleted sodium nitrate is placed in a suitable tumbler or inclinedrotating pellet coating bowl, and while under rotation the liquid nitrobody (preferably D. N. T. or M. N. T., T. N. T.) is added to therevolving and rolling mass, preferably in the form of a fine spray toform a slightly sticky film of this explosive material about each pelletof the nitrate.

As soon as the nitrate pellets are evenly coated the previously finelypowdered and intimately 5 mixed remaining ingredients are dusted inwhile the rolling is continued until each individual sodium nitratepellet is completely enveloped and enclosed in a layer of the thoroughlymixed powdered ingredients evenly distributed thereover, and boundthereto so as to form a substantially dry granular mass each grain ofwhich is a complete explosive unit.

The coating of the nitrate pellets as described should be carried out ata temperature sufficiently 15 above the setting point of the particularliquifiable nitro body being used so that this binding agent will remainin fluid condition until the completion of the coating operation.

Instead of the particular nitro bodies set out, others such as the nitroglycerine, benzenes, naphthalenes, etc. may be used, but those given inthe formula are preferred.

Also, the specific nitrate or perchlorate and oxidizable metal used asthe coating layer may be varied within the knowledge of explosiveengineers, but after my experiments I feel that the above simple formulawill meet all requirements in a blasting powder of this kind, though anysuch modifications as suggestedare intended to be included in the scopeof my appended claims.

' I am aware of pelleted nitrate of sodium as such being used inexplosives of the dynamite class, also the coating of ammonium nitratepellets with trimethylal-ethyl-methane-trinitrate, and also with othersubstances, but I am not aware of a blasting powder being heretoforeproduced in which each granule is a complete explosive unit in itselfformed of a central kernel of sodium nitrate entirely enclosed in thefortifying, sen- 40 sitizing and flame supporting agents in evendissemination and in adherent relation about its surface in proportionsto make of each a substantially balanced explosive unit. Nor do I knowof any comparable powder no matter of what constituted which has all ofthe valuable properties in comparison with black powder, as above setout.

Percussion tests of my improved blasting powder as above described, madeunder Bureau of Explosives requirements, Falling weight test, gave zeroresults with the 8 pound weight and 7 inch drop (steel on steel anvil)and actually required in excess of a 12 inch drop before explosion couldbe induced.

Similarly, frictional impact tests as per Bureau of Mines requirementsAnvil friction test, both with the fiber and steel shoe, producedneither explosion, nor ignition-in fact no distinguishable crackling,and furthermore Bureau of Mines tests for fumes reported Poisonous fumesnil.

The safety of my improved blasting powder over black powder isparticularly outstanding in ignition tests, for not only does theimproved powder withstand ignition from ordinary flame contact, such forinstance as burning a box of matches on top of a pile of it, but it willnot ignite if a teaspoonful of black powder is placed on top of a pileof it and the black powder ignited.

Having thus described my improved blasting composition, what I claim is:

1. A blasting powder comprising a loose mass of pellets having a sodiumnitrate center coated with a viscous film of an explosive nitric esterliquefiable at moderate temperatures forming a araaecs binder holding anouter layer of an intimate mixture of powdered ammonium nitrate,potassium perchlorate and powdered aluminum, so as to make each pellet acomplete explosive unit.

2. A blasting powder comprising a loose mass of pellets having a sodiumnitrate center coated with .a. viscous film of an explosive nitric esterliquefiable at moderate temperature forming a binder holding an outerlayer of an intimate mixture of a finely divided explosive including anitrate salt, a perchlorate, and an easily oxidizable metal.

3. A blasting powder comprising a loose mass of substantially uniformsize pellets having a sodium nitrate center coated with a viscous filmof an explosive nitric ester liquefiable at moderate temperaturesforming a binder holding an outer layer of an intimate mixture of afinely divided explosive including an oxygen yielding salt, and aneasily oxidizable metal.

LAUD S. BYERS.

